#include<stdio.h>
#include<malloc.h>
#define MaxSize 10
typedef char ElemType;
typedef struct
{
    ElemType data[MaxSize];
    int front,rear;     
} SqQueue;
void InitQueue(SqQueue *&q) 
{   q=(SqQueue *)malloc (sizeof(SqQueue));
    q->front=q->rear=0;
}
void DestroyQueue(SqQueue *&q)  
{
    free(q);
}
bool QueueEmpty(SqQueue *q) 
{
    return(q->front==q->rear);
}
bool enQueue(SqQueue *&q,ElemType e)    
{
    if ((q->rear+1)%MaxSize==q->front)  
        return false;
    q->rear=(q->rear+1)%MaxSize;
    q->data[q->rear]=e;
    return true;
}
bool deQueue(SqQueue *&q,ElemType &e)   
{
    if (q->front==q->rear)      
        return false;
    q->front=(q->front+1)%MaxSize;
    e=q->data[q->front];
    return true;
}
int length(SqQueue *&q){
    if(q->rear>q->front)
        return q->rear-q->front;
    else
        return q->front-q->rear;
}
int main()
{
	ElemType e;
	SqQueue *q;
	printf("环形队列的基本运算如下：\n");
	printf("(1)初始化队列q\n");
	InitQueue(q);
	printf("(2)依次进队列元素a、b、c\n");
 	enQueue(q,'a');
	enQueue(q,'b');
	enQueue(q,'c');
	printf("(3)队列%s\n",(QueueEmpty(q)?"空":"非空"));
	if(deQueue(q,e)==0)
	printf("队空不能出队\n");
	else
	printf("(4)出队一个元素%c\n",e);
	printf("(5)依次进队d、e、f\n");
	enQueue(q,'d');
	enQueue(q,'e');
	enQueue(q,'f');
	printf("(6)出队序列：");
	while(!QueueEmpty(q))
	{
		deQueue(q,e);
		printf("%c",e);
	}
	printf("\n");
	printf("(7)释放队列\n");
	free(q);
	return 0;
}